EA013275B1 - Template carbon monolithic tubes with shaped micro-channels and a method for making the same - Google Patents

Abstract

A method is disclosed for forming articles with template shaped channels 20, providing (a) mixing a precursor 18 with a fibrous template 10, (b) forming the mixture into a pre-determined shape, (c) curing the mixture to form a precursor composite 19, (d) carbonizing the precursor composite, and (e) decomposing the fibrous template to yield a shaped carbon article 21 with the template shaped channels 20.

Description

Smoking articles, especially cigarettes, typically include a shredded tobacco rod (usually in the form of a tobacco bag) surrounded by a paper jacket and a cylindrical filter aligned end-to-end with the tobacco rod. Typically, the filter contains a plug of cellulose acetate tow attached to the tobacco rod with cigarette paper.

After lighting the cigarette, the smoker draws in the mainstream smoke from the lit end of the cigarette. The retractable cigarette smoke first enters the front end portion of the filter and then passes through the rear portion adjacent to the mouthpiece end of the cigarette through which the consumer draws in smoke.

In order to achieve adequate filtration efficiency, materials such as coal were included in cigarette filters. A modern way of incorporating adsorbents into cigarette filters is the physical capture of adsorbent particles between cellulose acetate (AC) fibers. An improved and more expensive option is to place certain materials in the cavity between the AC plugs in a given configuration, such as a plug-gap-plug configuration, to limit the effect of the binder triacetin on the adsorbent.

Certain cigarettes include filter segments with adsorbents, such as activated carbon, in order to achieve the desired filter characteristics. Examples of such filters are described in US patent No. 2881770 (Toueu); 3353543 (8rgoi11 e! A1.); 3101723 (Zeidtai e! A1.) And 4481958 (Rasheg e! A1.) Certain commercially available filters have particles or granules of carbon (for example, activated carbon) that are alone or dispersed within an AC fiber bundle. Other commercially available filters have dispersed carbon fibers; while other commercially available filters have a structure called a plug-gap-plug, cavity filter or triple filter. Examples of commercially available filters are 8C8 IV Eia1 8ο1ίά Syageo1 Pg! E (double solid carbon filter) and Tp1e 8ο1ίά Syageoa1 P11! E (triple solid carbon filter) from IIgoia 1i! Egia! Ui1, b! B .; Tp1e Sauyu P11! Er (triple cavity filter) from Waitdaye; and AST from P11! goyia 1i! egia! yuya1, b! b. A detailed discussion of the properties and composition of cigarettes and filters is available in US Pat. Nos. 5,408,890 and 5,568,819, both of Seiyuu e! A1., the contents of which are incorporated by reference in this description.

Cigarette filter elements that include coal have the ability to remove the components of the mainstream smoke that passes through it. In particular, activated carbon tends to lower the levels of certain gas-phase components present in the mainstream smoke, resulting in a change in the organoleptic and toxicological properties of this smoke.

It would be desirable to provide a cigarette having a cigarette filter comprising coal and / or other materials capable of absorbing and / or adsorbing gas phase components present in the mainstream of the cigarette smoke, providing favorable absorption / adsorption, dilution and retraction characteristics to enhance consumer tolerance.

In addition, commercially acceptable activated carbons and molecular sieves are usually in granular and powder forms. The materials in these forms do not adhere the product, since granules or grains tend to settle when packaged inside a cigarette filter. Therefore, it is desirable to form a product having a rod configuration with channels and activated carbon, such as monolithic tubes for use in cigarette filtration, in order to achieve lower retraction resistance, a more finely ground substance and better product integrity.

According to a preferred embodiment of the invention, a method is provided comprising mixing an excess of a precursor of carbon materials, such as phenolic polymers, with fibrous patterns of low-carbon materials, such as polypropylene; giving the mixture the desired configuration, such as dragging the mixture through a paper, plastic, metal or glass tube; cutting off the excess mixture or cutting the tube to form a cylindrical configuration; curing the mixture in the tube to form a stable configuration precursor composite; handset movement; carbonization of the composite of the precursor in an inert medium or vacuum and the destruction of the fibrous patterns to obtain molded carbon products, such as monolithic tubes with formed channels.

Further, according to a preferred embodiment of the invention, carbon monolithic articles with formed channels are provided and are used to produce filters, more specifically cigarette filters, which are effective in reducing gas phase smoke components.

New features and advantages of the present invention in addition to those mentioned above will become apparent to those skilled in the art from reading the following detailed description in conjunction with the accompanying drawings, in which like reference numerals refer to like parts and in which:

FIG. 1 is a schematic diagram showing the steps of forming a cigarette filter with shaped channels according to the invention;

FIG. 2 is a side view of a cigarette with outer portions removed to show internal details, including a plug-gap-plug-plug filter with a filter including a carbon product according to

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FIG. 3 is a cross-sectional view of a fibrous template of a tri-lobed configuration according to the invention; FIG. 4 is a cross-sectional view of a four-lobed fibrous template according to the invention; FIG. 5 is a cross section of a U-shaped fibrous template according to the invention;

FIG. 6 is a cross-sectional view of inserted into each other Ι-shaped fibrous patterns according to the invention;

FIG. 7 is a cross section of a C-shaped fibrous template according to the invention;

FIG. 7 A is a cross-sectional view of a circular fibrous template according to the invention;

FIG. 7B is a cross-sectional view of the tubular fibrous template of the invention;

FIG. 8 is a cross-sectional view of a fibrous template of an irregular configuration according to the invention;

FIG. 9 - dependence of the comparative performance characteristics of the sample Ш4Е with the AC filter of the prior art and the filter cigarette according to the invention on the number of puffs characterized by the presence of

1,3-butadiene;

FIG. 10 shows the dependence of the comparative performance characteristics of a Ш4Е sample with a prior art AC filter and a filter cigarette according to the invention on the number of puffs characterized by the presence of acetone;

FIG. 11 shows the dependence of the comparative performance characteristics of a Ш4Е sample with an AC filter of the prior art and a filter cigarette according to the invention on the number of puffs characterized by the presence of benzene;

FIG. 12 shows the dependence of the comparative performance characteristics of a Ш4Е sample with an AC filter of the prior art and a filter cigarette according to the invention on the number of puffs characterized by the presence of formaldehyde.

In FIG. 1 and 2 show examples of the method and the final product according to the invention. It is easy to understand that the scope of this invention is not limited to these options. Rather, the scope of the present invention contains options that include a filter and a method for manufacturing the filter described herein.

As shown in FIG. 1, a typical method suitable for the mixing step may begin with a fiber template 10 with hollow channels 12. The fiber template 10 may be made of a material that will leave a small amount of residue upon thermal decomposition. Patterns 10 may also include low carbon materials. The preferred material for this purpose is polypropylene (PP).

The fibrous template 10 can be formed with a cross section of any configuration, including, without limitation, a three-lobed, four-lobed, Y-shaped, Ι-shaped, C-shaped, round, tubular and irregular configurations nested in each other, as indicated by the numbers 10-100 on FIG. 3-8 respectively. These configurations can be formed by extrusion, torsion, or in another way, as taught, for example, US Patent No. 5,057,368 (LAGDTAP1 A1.). The cross-sectional shape of the template provides longitudinal channels 12 that can be continuous and which are open to the surface of the template 10. The longitudinal channels 12 can have different configurations depending on the configuration of the template, as indicated by numbers 12A-12E in FIG. 3-8 respectively.

The fiber bundle of the template may be mixed with the carbon precursor in a container (not shown) to form a bundle 11 loaded with the precursor. The mixing step may be carried out in accordance with known techniques, such as those described in US Pat. Nos. 6,584,979 and 5772768 (Xie C1 A1.). Additional methods are known, as described, for example, in Highly efficient fiber filters formed by removal of acid gas (Sch2yu EGPs1ep1 Aab-Oak Vetoushd. apb ΕΒ1ίΐζ; Rde 154, 1999).

Certain levels of mixing or rotation of the container may be necessary in order to achieve continuously uniform impregnation of the patterns 10 with the precursor 18.

The carbon precursor materials used in the mixing step may be solid particles, gels, liquids, foam or mixtures thereof, which produce carbon or carbonoid materials when heated to an adequate temperature in an inert atmosphere or under vacuum. Suitable materials in these classes include, but are not limited to, phenolic polymers, petroleum sands, polyacrylonitrile, cellulose, cellulose derivatives, polyvinyl acetate (PVA), and mixtures thereof. Additional inorganic materials, such as molecular sieves, zeolites and silicates, may be included in the mixture to modify the pore distribution of the final carbonoid products. The phenolic polymers used can be uncured or partially cured novolac type resins with hardeners, or a resol (self-curing) type, or mixtures thereof. The production of porous molded carbon materials based on phenols from crushed partially cured resin is described, for example, in US patent No. 4917835 (Leag e1 a1.).

The fibrous pattern 10 may be processed as a random bundle or bundle 11 or in a manner such that the patterns or segments of the patterns may or may not be relatively aligned. The bundle 11, which may include one or many fibers, is then stretched with the precursor 18 of coal

- 2 013 275 cut form 14 with defined dimensions, which is shown in FIG. 1, for example a tube. The form may be paper, plastic, metal or glass.

An amount of coal precursor 18 may be included in the mixture so that patterns 10 are combined into a single product. Any voids, holes or annular gaps in the mold 14 may be filled with the precursor 18. The weight ratio of the coal precursor 18 to the polypropylene pattern 10, also called the load factor, is preferably in the range of 0.2-6, but not limited to.

Continuous impregnation processes using continuous rolls of pattern 10 fibers can be used to achieve similar results in a batch process. The patterns 10 can be pulled continuously through a container (not shown) containing a coal precursor 18, reassembled through a cone-shaped guide device (not shown) and combined in a continuous form (not shown) for further processing. Certain levels of mixing or rotation of the mold may be necessary in order to achieve continuously uniform impregnation. US Application No. 10/294346 A continuous method for impregnating adsorbent particulate matter in fibers with molded microcavities and fiber filters, fully incorporated herein by reference, describes typical processes for the continuous processing and impregnation of fibrous patterns.

After soaking mold 14 with a mixture including template 10 and precursor 18, redundant patterns 10 and / or beam precursor 18 may protrude from mold 14, as shown in FIG. 1. Blades 16 can be used to obtain the desired lengths, as well as to remove any excess template 10 of the beam 11 or the predecessor 18 protruding from the mold 14.

The precursor 18 and template 10 are then cured to form composite 19. To cure the mixture, conditions can be chosen to maintain the integrity of the templates 10, while the carbon precursor 18 is cured within the mold. Curing conditions depend significantly on the components in the coal precursor 18, especially the non-curing components used as binders. For example, curing can be achieved by heating in a gaseous medium of controlled composition at a temperature of about 120-160 ° C for about 15-60 minutes, although other temperatures and times are expected to be acceptable. A certain level of acid can be added to the phenolic precursor to speed up curing. After curing, the composite can retain its configuration, even if form 14 is removed.

The compound can then be carbonized (carbonized). For example, composite 19 can be heated in an inert atmosphere and / or under vacuum, which can decompose the template 10 and allow the composite 19 to form a patterned (made using the template) carbon article 21, such as a monolithic tube with voids or channels 20. Carbonization temperatures can be selected taking into account the used predecessor. For example, the temperature may be selected in the range of from about 600 to about 950 ° C., preferably about 850 ° C. Channels 20 derive their configuration from the configuration of templates 10. As with curing, the carbonization conditions may vary depending on the components in the coal precursor 18.

Different yields and configurations of coal can be obtained using different configurations and processing conditions. In the table. 1 lists 7 examples conducted using different template profiles and processing conditions to obtain different end channels. In each of the examples, the polypropylene template was mixed with a phenolic polymer-based carbon precursor. Patterns of 16 and 24 denier per thread (άρί) were used with diameters of approximately 60-120 μm. In the table. 1 diameters are designated as ά1. In the case of a three-part configuration, the diameter is a circle formed by a cross section. In the case of C-shape patterns or irregular configurations, ά1 is given by two numbers, which represent the relative length of the cross section in two orthogonal directions. The templates were loaded into a mold with a load factor between 0.2 and 6. Curing took place at approximately 150 ° C for approximately 25-40 minutes. After curing, the composites had a diameter of Ό1. A certain level of acid can be added to the phenolic precursor to accelerate this cure time. Carbonization was carried out at approximately 850 ° C for approximately 1-2 hours. After carbonization, the diameter of the product was reduced to Ό2. Coal yields were typically 30-40% by weight, depending on the polypropylene content of the composite precursor. The channels formed in the coal products received their configuration from the configuration of the template. The final diameter of the channels was ά2, while the final number of channels per square millimeter is represented as N.

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Table 1

Examples of processing conditions, configurations and final product

Way -> Template Load Curing, 150 ° C Carbonization, 850 ° C C-tube Channels Example Fiber s! 1 / m Km Fac- tor min O1 / mm Clock Exit % 02 / mm The form 62 / μm Ν / μμ ² one Three-share - 24 days * 80 1.3 25 8 2 32 6, 5 triad 100-143 168 2 Round -24 days 61 2.7 40 8 2 32 6 TO 28-50 207 3 Round -24 days 61 3.2 25 8 2 33 6 TO post office 168 4 Three-parted - 24 Day 80 4.8 35 8 2 36 5.5 triad 48-65 168 5 S-24 days 66X80 4.0 twenty nineteen one 36 12 FROM 55-75 351 6 Wrong-16 dn 60X12 0 5, 6 40 8 2 40 4 4ϋΟ 66-120 322 7 S-24 days 66X80 3,5 thirty nineteen one 33 12 FROM 55-75 391

* day - denier per thread.

Template carbon products 21 can be activated to produce high surface area adsorption materials for filtration applications. Many activation methods are known in the literature, such as heating with carbon dioxide or water vapor. For example, the template coal product from example 7 in table. 1 can be activated with carbon dioxide at a temperature of 950 ° C for approximately 40 minutes. At 25% burnup, the BET surface area is 1219 m ² / g, and the micropore volume (<20 A) is 0.4469 cm ³ / g. These values are comparable to those for activated carbon from coconut, which can also be used as an adsorbent in cigarette filters.

The carbon product may be further activated to enhance its filtering characteristics. For example, modified cigarette models containing 66 mg of activated template carbon can be obtained according to example 5 of table. 1 and coal can then be activated at a temperature of approximately 950 ° C. for approximately 30 minutes to achieve a burn-out rate of 30%. As shown in FIG. 2, the filters can be arranged so that conventional plugs 22 and 24 surround the template carbon article 21 prepared according to the present invention. Cigarettes can be smoked under the conditions of the Federal Trade Commission and the chemistry of smoke is analyzed by Fourier transform IR and chromatography-mass spectroscopy. As shown in the table. 2-3 and FIG. 9-12, the formed filters are effective for reducing a wide range of gas phase smoke components.

In the table. 2 shows a comparison of a standard 1K4E cigarette with a cigarette containing a coal product according to the invention with the characteristics described in example 5, table. 1. Kentucky Standard 1K4E is a filter cigarette manufactured by the Tobacco and Health Research Institute, University of Kentucky during these years for research purposes. The first row of the table. 2 shows the values of TID (completely ground substance (TPM, 1o1a1 ragyeyaaa shayeg)) of sample 1K4E.

The standard deviation is given with 1K4E data. The second row of the table. 2 shows the characteristics of the modified samples MT-66-1 and MT-66-2, which were made according to the invention and which were calculated as the difference in characteristics (in percent) to the control sample 1K4E. Modified samples MT-66-1 and MT-66-2 are cigarettes with the structure shown in FIG. 2, in which the plug 22 was 15 mm, the plug 24 was 7 mm and the carbon article 26 was 5 mm in axial length and weighed the coal product 66 mg, although any lengths and / or weights could be chosen.

The values reported for the modified MT-66-1 and MT-66-2 samples are given as a deviation from the 1K4E standard. The standard deviation from the control sample 1K4E more than three times is considered significant. As shown in the table. 2, the amount of acetaldehyde (AA), hydrogen cyanide (ΗΟΝ), methanol (MEOH), and isoprene (ISOP) in the total ground substance (TID) all decreased as a result of using the present invention.

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table 2

Control cigarette performance versus modified cigarette performance

Example ΆΆ (BEER) NSC (BEER) MEON (BEER) Isop (BEER) BEER mg ΒΤϋ Carbon fiber, mg 1B4E (PIVhU ^-3 ) 51.5 9.2 6, 2 23.7 13.3 140 0,0 Standard deviation 8% 4% nine% 8% 3% 5% Modified MT66-1 sample -32% -34% -32% -40% 16, 6 113 66 Modified MT66-1 sample -54% -32% -44% -38% 13.0 119 66

Tab. 3 further shows the benefits of the present invention.

The first column lists the characteristics and components common to cigarettes and cigarette smoke. The second column, called the Sigma control, shows the standard deviation of certain gas phase components in the 1B4T control cigarette. The third column, called MT 66, shows the changes in the levels of gas components, as a result of the use of filters made in accordance with the present invention, more specifically in example 5 of table. one.

Table 3

Change in the composition of gas-phase components __________________________________

Adsorbent-> Experiments Sigma control MT-66 Coal, mg 66 Comparison 9627-79 Gas phase components Change Carbon dioxide 5% No significant changes Ethane 6% No significant changes 1, Z-Butadiene 8% -41% Isoprene 5% -37% Cyclopentadiene 5% -46% 1, Z-Cyclohexadiene 17% -80% Methylcyclopentadiene nine% -84% Formaldehyde 14% -86% Acetone 12% -79% Diacetyl 5% -93% Methyl ethyl ketone 4% -90% Isovaleraldehyde nine% -7 9% Benzene 8% -82% Toluene 7% -92% Butyronitrile 8% -93% 2-methylfuran 4% -67% 2,5-dimethylfuran 5% -87% 1-methylpyrrole 8% -93% Keten eleven% -85%

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FIG. 9-12 further demonstrate how modified MT 66 samples reduce release

1.3- butadiene, acetone, benzene and formaldehyde from puff to puff.

For example, in FIG. Figure 9 shows the average amount of 1,3-butadiene in the mainstream smoke for different puffs of Kentucky standard ΙΚ.4Ρ cigarettes. 1,3-Butadiene in cigarette smoke is measured per puff. Cigarettes are smoked with a puff volume of 35 cm ³ for a duration of 2 s every 60 s. About selection

1.3-butadiene in sequential puffs has been reported for eight determinations from 1K.4P samples as well as MT 66. As shown in FIG. 9, the first puff is 15-20% of the total release from 1K.4R and less than 5% from MP 66 samples. The process was repeated seven more times according to known methods to obtain the graphs shown in FIG. 9-12.

As shown in FIG. 9-11, the content of gaseous components increases with each puff due to saturation of the filter. However, the formaldehyde content shown in FIG. 12 is reduced to almost zero for products including the present invention.

The above description of the invention explains and describes the present invention. Additionally, the disclosure shows and describes only preferred embodiments of the invention, but it should be understood that the invention is capable of being used in various other combinations, modifications and environments and is capable of changes or modifications within the framework of the inventive concept, as expressed herein, in proportion to the above teachings and / or to be used specialists in filter manufacturing technology, more specifically cigarette filters.

The options described above are further intended to explain the best known modes of carrying out the invention and to enable those skilled in the art to use the invention in one embodiment or another and with various changes required by specific applications or uses of the invention. Accordingly, the description is not intended to limit the invention to the form disclosed herein. It is further contemplated that the claims cover alternatives.

Claims (13)

CLAIM 1. A method of forming a coal product with patterned channels, comprising forming a fibrous template with a cross section having a three-lobed, four-lobed, Y-shaped, stylized образ-shaped, C-shaped, round or tubular configuration; mixing a coal precursor with a fiber template; giving the mixture a given configuration; curing the mixture to obtain a coal precursor composite of a given configuration; carbonization of the coal precursor composite and decomposition of the fibrous template to obtain a coal product with patterned channels. 2. The method according to claim 1, in which the fibrous template contains polypropylene. 3. The method according to claim 1, in which giving the mixture a given configuration includes pulling the mixture through the mold and trimming or cutting the mold into a discrete configuration. 4. The method according to claim 3, in which the specified form contains a material selected from the group consisting of paper, metal, plastic and glass. 5. The method according to claim 3, in which the specified form is a tube. 6. The method according to claim 4, in which the form is removed after the curing step and before the carbonization step. 7. The method according to claim 1, in which the carbonization is carried out in an inert medium, under vacuum or in a combination of these conditions. 8. The method according to claim 1, wherein the carbonization step and the decomposition step occur simultaneously. 9. The method according to claim 1, in which the molded carbon product is a monolithic tube. 10. The method according to claim 1, in which the stage of carbonization is carried out at a temperature of from about 600 to about 950 ° C. 11. The method of claim 10, wherein the coal precursor is a phenolic polymer. 12. The method of claim 10, further comprising activating a coal precursor. 13. A smoking article comprising a plug, a coal product adjacent to the plug with patterned channels having a three-piece, four-piece, U-shaped, stylized S-shaped, C-shaped, round or tubular configuration.